i was jumping around the other day, coming out of a drainage ditch to a flat surface. after one particular jump i felt a sharp pain in my neck that kinda radiated up to the back left of my head. it went away after a little bit, but today, while doing some work, it came back. does this sound familiar to anyone? any precautions i should take?

i think maybe my fork might've bottomed out, and the shock of the landing went up my arm to my neck...but i'm not sure (fork was fairly clean, i.e. no dust on the stanctions, and no zip ties).

The symptoms you describe are consistent with a pinched nerve. It is possible that with the hard landings you have been doing, you may have cause cervicle vetebra compression and/or cervicle disc herniation. I would recommend an evaluation by an orthopedic doctor and lay off the big drops and off road riding until you get your cervicle spine evaluated.